Mixing 720P with SD beta footage

We are shooting a spot on the HVX200 720P. We have some running footage on beta that we need to cut into the DVCPRO HD footage. Ultimately, the footage will be laid off to beta for broadcast. My plan was to place the 720P footage in an SD sequence, mix with the SD beta footage and then layoff to beta. I will conform the 720P footage to 4X3. Obviously the beta footage is 29.97. What frame rate should I capture the HVX 720 material with....29.97? Or do I capture at 23.98 and then let FCP do a pull down in the sequence. Suggestions?